The invention relates to a fluid-actuated diaphragm drive comprising a drive housing with two drive housing parts which are attached to one another axially in a joining region while together bounding a housing interior, wherein a drive diaphragm, which separates two axially adjacent operating chambers from each other in a fluid-tight manner is located in the housing interior and is motion-coupled to an output member wherein the drive diaphragm can be deflected axially by the application of fluid, controllable by means of a control passage structure formed at least partially in the drive housing, to at least one of the operating chambers, in order to induce an output movement of the output member.
The invention further relates to a valve assembly equipped with such a fluid-actuated diaphragm drive.
A diaphragm drive of the above type is known from DE 10 2013 016 350 B3 and comprises a drive housing which is surrounded on its outside by an additional shell housing for protection and which defines a housing interior divided into two fluid-actuable operating chambers by a drive diaphragm clamped between two drive housing parts of the drive housing. By a controlled application of fluid to at least one of the two operating chambers, the drive diaphragm can be deflected axially in one or the other direction for moving a rod-shaped output member attached to the drive diaphragm. The fluid is applied by means of a control passage structure which passes through the wall of the drive housing and comprises a plurality of control passages which terminate into the two operating chambers and through which a controlled supply and discharge of a drive fluid can be provided.
From EP 2 028 377 A2, a diaphragm drive is known which can be used as a drive source in a valve assembly and which has a housing in which a diaphragm tightly joined to the housing by its radially outer region is located. The diaphragm divides the housing interior into two operating chambers, to one of which a pressure fluid can be applied in a controlled manner while the other contains a spring device supported between the diaphragm and the housing and preloading the diaphragm and a valve spindle attached thereto towards a home position.